sverchok-impl-ifcsverchok

name	sverchok-impl-ifcsverchok
description	Use when generating IFC files from Sverchok geometry using IfcSverchok nodes. Prevents the critical mistake of not understanding SvIfcStore transient file management (data is purged on every full tree update -- use use_bonsai_file to persist). Covers the 31 specialized nodes, two geometry conversion modes, the 6-step IFC generation workflow, and Bonsai integration. Keywords: IfcSverchok, SvIfcStore, IFC from Sverchok, geometry to IFC, Bonsai integration, transient file, use_bonsai_file, IFC generation, node-based BIM, parametric IFC, generate IFC from nodes.
license	MIT
compatibility	Designed for Claude Code. Requires Blender 4.0+/5.x with Sverchok v1.4.0+, Bonsai addon, and IfcOpenShell 0.8.x.
metadata	{"author":"OpenAEC-Foundation","version":"1.0"}

sverchok-impl-ifcsverchok

Quick Reference

What Is IfcSverchok

IfcSverchok is an extension that bridges Sverchok parametric geometry with the IFC (Industry Foundation Classes) open BIM standard. It enables creation of native IFC models using visual node-based programming in Blender.

• 31 specialized nodes (24 IFC + 7 Shape Builder) for BIM model creation
• Two geometry modes: Blender mesh objects or raw Sverchok geometry to IFC
• Transient IFC file: single shared SvIfcStore.file managed across all nodes
• Bonsai integration: toggle to read/write Bonsai's active IFC file
• Status: Alpha (version 0.0.0) — expect stability issues

Dependency Chain

IfcSverchok
  ├── Bonsai (BlenderBIM) — must be enabled first
  ├── Sverchok v1.2+ — node tree framework
  └── ifcopenshell 0.8.x — IFC file manipulation

All three dependencies must be installed and enabled. IfcSverchok registers its nodes only when all dependencies are available.

Critical Warnings

NEVER use Blender undo inside an IfcSverchok node tree — this causes crashes due to the transient SvIfcStore.file becoming out of sync with Blender's undo state.

NEVER assume multiple IFC files can coexist — SvIfcStore manages exactly ONE transient file shared by ALL nodes in ALL trees. Running "Re-run all nodes" calls purge() which resets the entire file.

NEVER mix use_bonsai_file=True with SvIfcWriteFile export — writing overwrites Bonsai's active file state. Use one mode or the other.

NEVER expect IfcSverchok's process() to follow standard Sverchok conventions — SvIfcCore applies zip_long_repeat TWICE (double-nested), which is different from regular Sverchok nodes that apply it once.

ALWAYS include a geometry-to-representation conversion node (SvIfcBMeshToIfcRepr or SvIfcSverchokToIfcRepr) before SvIfcCreateEntity — entities without representations produce empty IFC files.

ALWAYS let ensure_hirarchy() handle missing spatial structure on export rather than manually creating IfcProject/IfcSite/IfcBuilding — the write node auto-completes the hierarchy.

Decision Tree

Need to create IFC from Sverchok geometry?
├── From Blender mesh objects → SvIfcBMeshToIfcRepr node
├── From Sverchok vertices/faces → SvIfcSverchokToIfcRepr node
├── From IFC ShapeBuilder profiles → SvIfcSbRectangle → SvIfcSbExtrude → SvIfcSbRepresentation
└── From existing IFC file → SvIfcReadFile node

Need to build IFC hierarchy?
├── Quick setup → SvIfcQuickProjectSetup (creates project + site + building + storey)
├── Manual hierarchy → SvIfcAddSpatialElement for each level
└── Minimal → Just use SvIfcCreateEntity + SvIfcWriteFile (ensure_hirarchy fills gaps)

Need to query IFC data?
├── By STEP ID → SvIfcById node
├── By GlobalId → SvIfcByGuid node
├── By IFC class → SvIfcByType node
├── By selector query → SvIfcByQuery node
└── Read attributes → SvIfcReadEntity node

Need Bonsai integration?
├── Write to Bonsai's file → Toggle "Use Bonsai File" button, then run nodes
├── Read Bonsai's file → Toggle "Use Bonsai File", use query nodes
└── Export standalone → Keep use_bonsai_file=False (default), use SvIfcWriteFile

---

Essential Patterns

Pattern 1: SvIfcStore: Transient File Management

# IfcOpenShell 0.8.x / IfcSverchok
# SvIfcStore manages a SINGLE transient IFC file across the node tree.

class SvIfcStore:
    file: Union[ifcopenshell.file, None] = None
    id_map: dict[str, Any] = {}        # node_id -> created entity data
    schema_identifiers = ["IFC4", "IFC2X3"]
    use_bonsai_file = False

    @staticmethod
    def purge() -> None:
        """Reset all state. Called before each full node tree re-run."""
        SvIfcStore.file = None
        SvIfcStore.id_map = {}

    @staticmethod
    def get_file() -> ifcopenshell.file:
        """Return the current transient file.
        Creates boilerplate IFC4 file if none exists.
        Returns Bonsai's file when use_bonsai_file is True."""
        if SvIfcStore.use_bonsai_file:
            return tool.Ifc.get()
        if SvIfcStore.file is None:
            SvIfcStore.create_boilerplate()
        return SvIfcStore.file

Key behaviors:

• purge() runs at the start of every full tree re-evaluation
• id_map tracks which node created which IFC entities (keyed by node_id)
• get_file() lazily creates a boilerplate IFC4 file on first access
• Only ONE file exists at a time — no multi-file workflows

Pattern 2: SvIfcCore: Double-Nested Input Processing

# IfcOpenShell 0.8.x / IfcSverchok
# SvIfcCore applies zip_long_repeat TWICE: different from standard Sverchok.

from sverchok.data_structure import zip_long_repeat

class SvIfcCore:
    sv_input_names: list[str]

    def process(self) -> None:
        # Gather all inputs
        sv_inputs_nested = []
        for name in self.sv_input_names:
            sv_inputs_nested.append(self.inputs[name].sv_get())

        # FIRST zip_long_repeat: across objects (outer nesting level)
        for sv_input_nested in zip_long_repeat(*sv_inputs_nested):
            # SECOND zip_long_repeat: within each object (inner nesting level)
            for sv_input in zip_long_repeat(*sv_input_nested):
                sv_input = list(sv_input)
                self.process_ifc(*sv_input)

Why double-nested: Sverchok data is [[obj1_data], [obj2_data]]. The first zip matches across inputs at the object level. The second zip iterates within each object, processing individual items. This allows a single SvIfcCreateEntity node to create multiple entities across multiple objects.

Pattern 3: Sverchok Geometry to IFC Representation

# IfcOpenShell 0.8.x / IfcSverchok
# Converting Sverchok geometry (vertices, edges, faces) to IFC representation.
# Node: SvIfcSverchokToIfcRepr

# In a Sverchok node tree, connect:
# [Plane Generator] → Vertices → [SvIfcSverchokToIfcRepr] → Representation → [SvIfcCreateEntity]
#                   → Faces    → /

# SvIfcSverchokToIfcRepr internally:
# 1. Normalizes vertex/edge/face data to 4-deep nesting
# 2. Zips geometry objects together
# 3. For each geometry object:
#    - Creates IfcCartesianPointList3D from vertices
#    - Creates IfcTriangulatedFaceSet or IfcPolygonalFaceSet from faces
#    - Wraps in IfcShapeRepresentation with context_type/context_identifier
# 4. Outputs IFC representation entity IDs

Pattern 4: Blender Mesh to IFC Representation

# IfcOpenShell 0.8.x / IfcSverchok
# Converting Blender mesh objects to IFC representations.
# Node: SvIfcBMeshToIfcRepr

# In a Sverchok node tree, connect:
# [Objects In] → Objects → [SvIfcBMeshToIfcRepr] → Representations → [SvIfcCreateEntity]
#                                                 → Locations      → /

# SvIfcBMeshToIfcRepr internally:
# 1. Takes Blender mesh objects as input
# 2. Separates loose parts into individual geometry sets
# 3. Generates IFC representation per object
# 4. Preserves world matrices as Locations output
# 5. Outputs: Representations (IFC repr IDs) + Locations (4x4 matrices)

# Inputs:
#   context_type: "Model" or "Plan"
#   context_identifier: "Body", "Annotation", "Box", or "Axis"
#   target_view: geometric target view
#   blender_objects: list of Blender mesh objects

Pattern 5: 6-Step IFC Generation Workflow

# IfcOpenShell 0.8.x / IfcSverchok
# Complete workflow for generating a valid IFC file from Sverchok.

# Step 1: Generate Geometry
# Use any Sverchok generator nodes (Box, Plane, Cylinder, etc.)
# OR use ShapeBuilder nodes (SvIfcSbRectangle → SvIfcSbExtrude)
# OR use Blender Objects In node

# Step 2: Convert to IFC Representation
# [SvIfcSverchokToIfcRepr]: from Sverchok vertices/edges/faces
# [SvIfcBMeshToIfcRepr]   : from Blender mesh objects
# [SvIfcSbRepresentation] : from ShapeBuilder geometry

# Step 3: Create IFC Entities
# [SvIfcCreateEntity]
#   IfcClass = "IfcWall"  (or IfcSlab, IfcColumn, etc.)
#   Names = "Wall_001"
#   Representation = (from Step 2)

# Step 4: Build Spatial Hierarchy
# [SvIfcAddSpatialElement]
#   IfcClass = "IfcBuildingStorey"
#   Elements = (from Step 3)
# Or skip: ensure_hirarchy() auto-completes on export

# Step 5: Add Properties (Optional)
# [SvIfcAddPset]
#   Name = "Pset_WallCommon"
#   Properties = '{"IsExternal": true, "LoadBearing": false}'

# Step 6: Export
# [SvIfcWriteFile]
#   path = "/path/to/output.ifc"
#   Triggers ensure_hirarchy() automatically

Pattern 6: ShapeBuilder Workflow

# IfcOpenShell 0.8.x / IfcSverchok
# Using ShapeBuilder nodes to create IFC geometry natively.

# ShapeBuilder creates geometry directly as IFC entities,
# bypassing Blender/Sverchok mesh conversion entirely.

# Node chain:
# [SvIfcSbRectangle] → profile → [SvIfcSbExtrude] → shape → [SvIfcSbRepresentation] → repr
#   XDim = 0.3                     Magnitude = 3.0
#   YDim = 0.2

# SvIfcSbRectangle creates an IfcRectangleProfileDef
# SvIfcSbExtrude extrudes the profile into an IfcExtrudedAreaSolid
# SvIfcSbRepresentation wraps into IfcShapeRepresentation

# Available ShapeBuilder nodes:
# SvIfcSbRectangle: rectangle profile
# SvIfcSbExtrude  : extrusion along axis
# SvIfcSbRepresentation: wraps to shape representation
# SvSbMesh        : creates IFC mesh from vertices/polygons
# SvSbPolyline    : creates IFC polyline from vertices
# SvSbShapeOutput : converts IFC shape back to Sverchok geometry
# SvIfcSbTest     : debug/testing node

Pattern 7: Automatic Hierarchy Completion (ensure_hirarchy)

# IfcOpenShell 0.8.x / IfcSverchok
# Called automatically by SvIfcWriteFile before export.

# ensure_hirarchy() performs these steps:
# 1. Creates a default IfcBuilding if none exists in the file
# 2. Assigns orphaned IfcBuildingStorey elements to the building
# 3. Assigns uncontained IfcElement instances to the building
# 4. Creates a default IfcSite if none exists
# 5. Links Building → Site → Project

# This means a minimal workflow can skip manual hierarchy:
# [Geometry] → [Repr] → [CreateEntity] → [WriteFile]
# ensure_hirarchy() fills in Project/Site/Building automatically.

# NOTE: The function is named "ensure_hirarchy" (typo preserved from source).
# Do NOT attempt to call "ensure_hierarchy": the correct name has no second 'e'.

---

Common Operations

Complete Node Catalog (31 Nodes)

IFC Nodes (24)

Node Class	Label	Purpose
SvIfcCreateFile	IFC Create File	Creates new empty IFC file with specified schema
SvIfcReadFile	IFC Read File	Opens existing IFC file from disk
SvIfcWriteFile	IFC Write File	Exports transient file to disk (calls ensure_hirarchy)
SvIfcCreateEntity	IFC Create Entity	Creates IFC entities with geometry and placement
SvIfcCreateShape	IFC Create Blender Shape	Converts IFC entities to Blender mesh objects
SvIfcReadEntity	IFC Read Entity	Reads entity, exposes all attributes as outputs
SvIfcPickIfcClass	IFC Class Picker	UI picker for IFC classes by product category
SvIfcById	IFC By Id	Retrieves entities by STEP file ID
SvIfcByGuid	IFC By Guid	Retrieves entities by GlobalId
SvIfcByType	IFC By Type	Queries all entities of a given type
SvIfcByQuery	IFC By Query	Queries using IfcOpenShell selector syntax
SvIfcAdd	IFC Add	Adds an entity to the IFC file
SvIfcAddPset	IFC Add Pset	Creates or edits property sets on elements
SvIfcAddSpatialElement	IFC Add Spatial Element	Creates spatial elements, assigns contained elements
SvIfcRemove	IFC Remove	Removes an entity from the IFC file
SvIfcGenerateGuid	IFC Generate Guid	Generates IFC-compliant GUID
SvIfcGetProperty	IFC Get Property	Retrieves property value from a property set

IFC Shape Builder Nodes (7)

Node Class	Label	Purpose
SvIfcSbRectangle	IFC Rectangle	Creates IFC rectangle profile via ShapeBuilder
SvIfcSbExtrude	IFC Extrude	Extrudes IFC profile along axis
SvIfcSbRepresentation	IFC Representation	Wraps items into IfcShapeRepresentation
SvIfcSbTest	IFC SB Test	Test/debug node
SvSbShapeOutput	IFC Shape Output	Converts IFC shape to Sverchok geometry
SvSbMesh	IFC Mesh	Creates IFC mesh from vertices and polygons
SvSbPolyline	IFC Polyline	Creates IFC polyline from vertices

SvIfcStore Static Methods

Method	Signature	Purpose
purge	() -> None	Resets file, id_map. Called before full re-run
get_file	() -> ifcopenshell.file	Returns transient file (creates if needed)
create_boilerplate	() -> None	Creates minimal IFC4 file with header data

SvIfcStore Class Attributes

Attribute	Type	Purpose
file	ifcopenshell.file | None	The single transient IFC file
id_map	dict[str, Any]	Maps node_id to created IFC entity data
schema_identifiers	list[str]	Supported schemas: ["IFC4", "IFC2X3"]
use_bonsai_file	bool	When True, get_file() returns Bonsai's file

Geometry Mode Comparison

Aspect	SvIfcBMeshToIfcRepr	SvIfcSverchokToIfcRepr
Input source	Blender mesh objects	Sverchok vertices/edges/faces
Loose parts	Auto-separated	N/A (already separate objects)
World matrix	Preserved as Locations output	Not applicable
Outputs	Representations + Locations	Representations only
Use when	Working with existing Blender geometry	Working with procedural Sverchok geometry

Known Issues and Limitations

Issue	Impact	Workaround
Blender crashes during undo	Data loss	Save frequently, avoid undo in IFC trees
Single transient file	No multi-file workflows	Process one IFC file at a time
No type/material library	Cannot manage IfcTypeProduct or IfcMaterial	Use ifcopenshell.api directly via SvIfcApi node
Limited geometry types	Only basic shapes via ShapeBuilder	Use SvIfcSverchokToIfcRepr for complex geometry
No infrastructure support	IfcBridge, IfcRoad unavailable	Not supported in current version
No MVD validation	No compliance checking	Validate externally after export
No quantity takeoff	No IfcElementQuantity nodes	Use ifcopenshell.api via SvIfcApi node

---

Reference Links

• references/methods.md — Complete API signatures for SvIfcStore, SvIfcCore, all 31 nodes, and ensure_hirarchy
• references/examples.md — Working code examples for IFC generation workflows, ShapeBuilder, Bonsai integration
• references/anti-patterns.md — What NOT to do with IfcSverchok, with explanations

Cross-References

• ifcos-core-concepts — IfcOpenShell fundamentals
• ifcos-syntax-elements — IFC element types and attributes
• ifcos-impl-creation — Creating IFC entities with ifcopenshell.api
• bonsai-core-architecture — Bonsai addon architecture

Official Sources

• https://github.com/IfcOpenShell/IfcOpenShell/tree/v0.8.0/src/ifcsverchok
• https://community.osarch.org/discussion/284/sverchok-ifc